We introduce a coupled mechano-chemical peridynamic model to describe stress corrosion cracking. In this model, two mechanisms, stress-dependent anodic dissolution and diffuse corrosion layer-assisted fracture, are considered to influence pitting and crack propagation in stress corrosion cracking. Diffusion peridynamic bonds (acting as dissolution bonds at the solid/liquid interface) and mechanical peridynamic bonds are used to represent the interactions between material points. Mechanical bonds can be damaged by mechanical stretching or by anodic dissolution. The magnitude of the dissolution fluxes for diffusion peridynamic bonds depends on both mechanical deformation and the applied electrical potential. The coupling between anodic dissolution and mechanical damage leads to cracks that initiate in the corrosion damage layer and propagate into the bulk. A 2D three-point bending/corrosion test demonstrates the concept. We verify the model in 3D using an experimental test from the literature for the case of stress-corrosion cracking process in a steam turbine steel sample. The model's results capture the pit-to-crack transition time, the pit size and shape at fracture, as well as the morphology of cracks that spring from, and connect the pits.

我们引入了一个耦合的机械化学的近动力学模型来描述应力腐蚀开裂。在该模型中，考虑了两种机制，即应力相关的阳极溶解和弥散腐蚀层辅助的断裂，影响应力腐蚀裂纹中的点蚀和裂纹扩展。扩散蠕动键（充当固/液界面的溶解键）和机械蠕动键用于表示物质点之间的相互作用。机械键可因机械拉伸或阳极溶解而损坏。扩散绕动键的溶解通量的大小取决于机械变形和施加的电势。阳极溶解与机械损伤之间的耦合会导致裂纹，这些裂纹在腐蚀损伤层中引发并扩散到整个主体中。二维三点弯曲/腐蚀测试证明了这一概念。我们使用来自文献的实验测试以3D方式验证了该模型在汽轮机钢样品中应力腐蚀开裂过程中的情况。该模型的结果捕获了从坑到裂缝的过渡时间，裂缝处的坑尺寸和形状，以及从坑中连接出来的裂缝的形态。